Anaplastic transformation in verrucous carcinoma of the oral cavity after radiation therapy.

Abstract

Verrucous carcinoma of the oral cavity has been established as a distinctive clinical and pathologic entity (1, 2, 11, 15). Typically, the lesion appears as a slow-growing warty mass on the gingival or buccal mucosa of an elderly patient. Histologically, it is characterized by a well differentiated pattern of squamous epithelium in abundant papillomatous hyperkeratotic folds. The tumor slowly invades deeper structures, including bone, but rarely metastasizes (1, 2, 7, 15). A predilection for the mucosa of the oral cavity of tobacco chewers has been noted (1,2, 11), but the lesion also occurs in the larynx and on the squamous mucosa of the vulva, vagina, and glans penis (15). Reports on satisfactory results of treatment of verrucous carcinoma with surgery and diathermy have appeared in the literature (11, 15, 21). Although a large number of cases of squamous carcinoma of the oral cavity have been irradiated (4, 8, 15, 19), the poor response of verrucous carcinoma to this particular method of treatment has not been emphasized. The tendency to local recurrence is well known (1, 2, 7), and the appearance of other squamous carcinomas of a higher grade of malignancy elsewhere in the oral cavity has been reported in some of these patients (11, 15). The present study analyzes the results in 8 cases of verrucous carcinoma treated between 1954 and 1962, in which the initial primary therapy was external or interstitial irradiation. A change in the character of the lesion from differentiated to undifferentiated tumor with increased aggressiveness after radiation therapy is described in 3 cases. Clinical Material Seventeen cases of verrucous carcinoma of the oral cavity were observed at Barnes Hospital between 1954 and 1962. Thirteen were in males and 4 in females. The majority of the patients were in the sixth and seventh decades. Some of these cases comprise a portion of a pathological study to be reported elsewhere (15). Nine patients were treated by excision of the lesion. In 8, radiation therapy was the initial method of treatment (Table I). One patient with a primary lesion in the nasal cavity is included in this series. None had clinical evidence of lymph node metastases when first seen. Several modalities of radiation therapy were employed in the management of these patients. In 4, orthovoltage was used, with 250 kv, 15 ma, copper and aluminum nitration, h.v.l. varying between 2.5 and 3.75 mm copper. Twenty-two Mev x-rays from a betatron were administered in one case and cobalt 60 in another. The other 3 patients received a combination of interstitial irradiation with radon seeds (2) or radium (1) plus external orthovoltage therapy. Opposed lateral portals, in some cases supplemented with a frontal field to encompass the clinical extent of the lesion with an adequate margin, were used. The total tumor doses varied from 5,000 to 7,500 rads, administered over a period of five to seven weeks.